package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;




    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->  {
            this.queryBlogUser( blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result likeBlog(Long id) {
        //判断当前用户是否点赞
        // 获取当前用户
        Long userId = UserHolder.getUser().getId();
        //判断是否点过赞
        String key = "blog:liked:" + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //未点赞，RedisSet+1
        if (score == null ){
            boolean isSuccess = update()
                    .setSql("liked = liked + 1")
                    .eq("id", id).update();
            //更新数据库
            if (isSuccess){
                stringRedisTemplate.opsForZSet().add(key, userId.toString(),System.currentTimeMillis());
            }
        }else{
            //已点赞，RedisSet-1
            boolean isSuccess = update()
                    .setSql("liked = liked - 1")
                    .eq("id", id).update();
            //更新数据库
            if (isSuccess){
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        // 1. 查询Top5点赞用户ID
        String key = "blog:liked:" + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);

        // 2. 处理空列表情况（无点赞用户）
        if (top5 == null || top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }

        // 3. 转换ID列表并查询用户
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids)
                .last("ORDER BY FIELD(id," + idStr + ")")
                .list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        boolean result = save(blog);
        if (!result){
            return Result.fail("新增笔记失败！");
        }
        //查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        for (Follow follow : follows) {
            Long userId = follow.getUserId();
            String key = "feed:" + userId;
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(),System.currentTimeMillis());
        }
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //获取当前用户
        Long userId = UserHolder.getUser().getId();
        //查收件箱里面的所有笔记
        String key = "feed:" + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        List<Long> ids =new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        //解析数据blogId、score（时间戳）、offset
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples){
            ids.add(Long.valueOf(tuple.getValue()));

            long time = tuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else{
                minTime = time ;
                os = 1;
            }
        }
        //根据id查询blog，封装并返回
        String idStr = StrUtil.join(",", ids);
        List< Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Blog blog : blogs){
            queryBlogUser(blog);
            isBlogLiked(blog);
        }
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);

        return Result.ok(scrollResult);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryBlogById(Long id) {
        //
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("笔记不存在！");
        }
        queryBlogUser( blog);
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        UserDTO userDTO = UserHolder.getUser();
        if(userDTO == null){
            return;
        }
        Long userId = UserHolder.getUser().getId();
        String key = "blog:liked:" + blog.getId();
        Double  score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }
}
